Breast cancer risk factors in relation to molecular subtypes in breast cancer patients from Kenya

Breast Cancer Research

Peter Bird¹  Kevin Gardner²  Rajendra Chauhan³  Zahir Moloo³  Mansoor Saleh³  Miriam Mutebi³  Sitna Mwanzi³  Ronald Wasike³  Asim Jamal Shaikh³  Shahin Sayed⁴  Francis W. Makokha⁵  Xiaohong R. Yang⁶  Shaoqi Fan⁶  Faith Wambui Njoroge⁷  Raymond Oigara⁸  Jonine D. Figueroa⁹  Richard Naidoo^1,10  Dhirendra Govender^1,11  Pumza Magangane^1,12 

[1]AIC Kijabe Hospital, Kijabe, Kenya

[2]Columbia University Medical Centre, New York, USA

[3]Department of Pathology, Aga Khan University, Nairobi, Kenya

[4]Department of Pathology, Aga Khan University, Nairobi, Kenya

[5]University of Cape Town, Cape Town, South Africa

[6]Mount Kenya University, Thika, Kenya

[7]National Cancer Institute of the National Institutes of Health (NCI/NIH) Bethesda, Rockville, Maryland, USA

[8]Nyeri Provincial General Hospital, Nyeri, Kenya

[9]St. Mary’s Mission Hospital, Nairobi, Kenya

[10]Kisii University, Kisii, Kenya

[11]The University of Edinburgh, Edinburgh, UK

[12]University of Cape Town, Cape Town, South Africa

[13]University of Cape Town, Cape Town, South Africa

[14]PathCare, Cape Town, South Africa

[15]University of the Witwatersrand, Johannesburg, South Africa

关键词: Breast cancer;    Molecular subtypes;    Risk factors;    Kenya;    Sub-Saharan Africa;   

DOI  :  10.1186/s13058-021-01446-3

来源: Springer

【 摘 要 】

BackgroundFew studies have investigated risk factor heterogeneity by molecular subtypes in indigenous African populations where prevalence of traditional breast cancer (BC) risk factors, genetic background, and environmental exposures show marked differences compared to European ancestry populations.MethodsWe conducted a case-only analysis of 838 pathologically confirmed BC cases recruited from 5 groups of public, faith-based, and private institutions across Kenya between March 2012 to May 2015. Centralized pathology review and immunohistochemistry (IHC) for key markers (ER, PR, HER2, EGFR, CK5-6, and Ki67) was performed to define subtypes. Risk factor data was collected at time of diagnosis through a questionnaire. Multivariable polytomous logistic regression models were used to determine associations between BC risk factors and tumor molecular subtypes, adjusted for clinical characteristics and risk factors.ResultsThe median age at menarche and first pregnancy were 14 and 21 years, median number of children was 3, and breastfeeding duration was 62 months per child. Distribution of molecular subtypes for luminal A, luminal B, HER2-enriched, and triple negative (TN) breast cancers was 34.8%, 35.8%, 10.7%, and 18.6%, respectively. After adjusting for covariates, compared to patients with ER-positive tumors, ER-negative patients were more likely to have higher parity (OR = 2.03, 95% CI = (1.11, 3.72), p = 0.021, comparing ≥ 5 to ≤ 2 children). Compared to patients with luminal A tumors, luminal B patients were more likely to have lower parity (OR = 0.45, 95% CI = 0.23, 0.87, p = 0.018, comparing ≥ 5 to ≤ 2 children); HER2-enriched patients were less likely to be obese (OR = 0.36, 95% CI = 0.16, 0.81, p = 0.013) or older age at menopause (OR = 0.38, 95% CI = 0.15, 0.997, p = 0.049). Body mass index (BMI), either overall or by menopausal status, did not vary significantly by ER status. Overall, cumulative or average breastfeeding duration did not vary significantly across subtypes.ConclusionsIn Kenya, we found associations between parity-related risk factors and ER status consistent with observations in European ancestry populations, but differing associations with BMI and breastfeeding. Inclusion of diverse populations in cancer etiology studies is needed to develop population and subtype-specific risk prediction/prevention strategies.

【 授权许可】

CC BY